Tag Archives: Robert Smith

A group of scientists have been examining the “heart” of Old
Faithful — Yellowstone National Park’s most famous geyser. These
researchers are focused on figuring out exactly what causes this
rare geological formation to beat faithfully and forcefully,
beginning long before the geyser was discovered in 1870.

University of Utah researchers have finally produced substantial
images of the geological anatomy of the geyser, complete with its
natural underground ductwork that causes it to flush regularly.

“Here’s the iconic geyser of Yellowstone,” declared Robert
Smith, researcher and professor of geology and geophysics. “It’s
known around the world, but the complete geologic plumbing of
Yellowstone’s Upper Geyser Basin has not been mapped, nor have we
studied how the timing of eruptions is related to precursor ground
tremors before eruptions.”

Smith, who has spent 60 years working in America’s first
national park, said in a news release that he and
his associates may have cracked the mystery by mapping the
underground pathways that eventually carry steam and heated water
to the surface vent, which spews out every 44 to 125 minutes. The
mapping effort relied on a dense network of portable seismographs
and new methods of analyzing the data.

Results of the study are published in
Geophysical Research Letters. The paper’s lead author is
doctoral student Sin-Mei Wu. The news release was written by
science writer Paul Gabrielsen of the University of Utah’s
communications department.

Yellowstone National Park is underlain by two reservoirs of
active magma, one about 3 miles down, the other about 25. They are
the power behind the unusual formations and ongoing venting that
form chemical lakes and springs as well as the explosive
geysers.

The anatomy of Old Faithful
geyser, as revealed in new studiesImage: Sin-Mei Wu

Smith along with fellow researchers Jamie Farrell and Fan-Chi
Lin have spent years characterizing the magma reservoirs. They
track the small rumblings of ground movement, as recorded on
seismometers, and then plot out the underground structures.

“We try to use continuous ground shaking produced by humans,
cars, wind, water and Yellowstone’s hydrothermal boilings and
convert it into our signal,” Lin explained in the news release. “We
can extract a useful signal from the ambient background ground
vibration.”

About 30 permanent seismometers around the park monitor ground
shaking and earthquakes at a cost of about $10,000 each. In 2015,
the work expanded. Some 133 small seismometers, which cost about
$2,000 each, were deployed for two weeks around Old Faithful and
Geyser Hill. These cheaper seismometers were developed by the
company FairfieldNodal for
oil and gas exploration, but they became a key to understanding Old
Faithful’s seismic activity.

Small portable seismometers
were the key to tracing underground formations.Photo: Paul Gabrielsen

The data show patterns of intense tremors lasting about 60
minutes followed by 30 minutes of quiet. The eruption of Old
Faithful occurs not during the peak of shaking but just before
everything goes quiet.

The cycle begins after an eruption when the geyser’s underground
reservoir starts filling up with water. Pressure in the reservoir
builds up from heated water and lots of aqueous bubbles, which
rumble until an eruption occurs. The eruption cools the water very
quickly causing an implosion that registers on the seismometers
before everything stops and the cycle starts again.

Typically, seismic imaging uses a man-made source to shake the
ground, such as setting off an explosion or banging a hammer on a
metal plate in the ground. Lin and Wu developed a method of sifting
useful signals from the natural hydrothermal rumblings, thanks to
the number and location of small seismometers.

“It’s amazing that you can use the hydrothermal source to image
the structure here,” Wu said.

The data showed that tremors from Old Faithful were not reaching
the western boardwalk, while seismic waves from another
hydrothermal feature also slowed and scattered in the same general
area. That pointed to some kind of underground feature that became
the focus of intense study using a dense network of the small
seismometers. The researchers believe they pinpointed the location
of Old Faithful’s long-sought reservoir.

Wu estimates that the reservoir, a network of fractured rock, is
about 650 feet across and can hold more than 79 million gallons of
water, as compared to Old Faithful’s eruption, which releases about
8,000 gallons at a time.

“Although it’s a rough estimation, we were surprised that it was
so large,” Wu said.

The research team is returning to the park this winter for more
studies into the subsurface structure and to develop higher
resolution images at Old Faithful. Smith hopes to use similar
methods to reveal hidden features in other areas, including the
Norris Geyser Basin — the hottest geothermal area in the park.

Meanwhile, National Park Service officials would like to know if
any of the geothermal features and underlying magma might pose a
future risk to people and buildings in the park, especially around
the large visitor center at Old Faithful. The underground mapping
could help with those questions.

Lin credits Smith’s long-term relationship with the park as
opening the door to the research being conducted by the University
of Utah. “You need new techniques,” he said, “but also those
long-term relationships.”

Old Faithful was named on Sept. 18, 1870, by members of the
Washburn-Langford-Doane Expedition. As later described in Nathanial
P. Langford’s account of the expedition:

“It spouted at regular intervals nine times during out stay, the
columns of boiling water being thrown from 90 to 125 feet at each
discharge, which lasted from 15 to 20 minutes. We gave it the name
‘Old Faithful.’”

In those days, nobody could explain why Old Faithful acted the
way it did, but some of the early visitors put the geyser to a
practical use. In his 1883 guide for tourists, Henry J. Winser
wrote:

“Old Faithful is sometimes degraded by being made a laundry.
Garments placed in the crater during quiescence are ejected
thoroughly washed when the eruption takes place. Gen. Sheridan’s
men, in 1882, found that linen and cotton fabrics were uninjured by
the action of the water, but woolen clothes were torn to
shreds.”

It would be another 135 years before the plumbing of this
natural “laundry” would be explained with the use of advanced
technology.